Sound ameliorates visual contrast threshold
Poster Presentation

Anne Caclin
INSERM U821, Lyon, France

Patrick Bouchet
INSERM U821, Lyon, France

Jacques Pernier
INSERM U821, Lyon, France

Marie-Hélène Giard
INSERM U821, Lyon, France

     Abstract ID Number: 16
     Full text: Not available
     Last modified: March 2, 2007
     Presentation date: 07/06/2007 10:00 AM in Quad Maclauren Hall
     (View Schedule)

Abstract
Compelling evidence has been gathered for the existence of strong crossmodal interactions implicating early sensory processing stages, in a variety of domains such as speech perception, spatial processing, object recognition. However, whether a stimulation in an irrelevant sensory modality can ameliorate the threshold for detection of a target in another modality remains controversial. Most of the behavioural findings reported so far suggesting that an irrelevant modality (e.g., auditory) facilitates the detection of targets in the modality of interest (e.g., visual) at the perceptual threshold have been obtained in situations where it is difficult to disambiguate genuine perceptual effects from post-perceptual (judgmental) bias.

We have therefore undertaken measurements in humans of the contrast thresholds just enabling the detection of visual targets (Gabor patches), using a forced-choice task, hence a criterion-free methodology, with and without irrelevant auditory stimulation (bursts of noise). Our results suggest that irrelevant auditory stimulation can indeed lower the visual contrast threshold, even in this situation were post-perceptual biases should be minimal. We are currently investigating the effects of some characteristics of the stimuli on this audio-visual effect at threshold.